Free Inpatient Obstetric Practice Test
1. The greatest risk of herpes simplex virus (HSV) transmission to a newborn who is delivered vaginally occurs with:
a. an active recurrent (secondary) HSV outbreak at the time of delivery.
b. a history of a primary HSV outbreak early in pregnancy without active disease at the time of delivery.
c. an active primary HSV outbreak at the time of delivery.
2. The parameter of fetal heart monitoring that is most predictive of fetal compromise is:
a. baseline fetal tachycardia.
b. minimal or absent fetal heart rate variability.
c. variable decelerations.
3. Women who experience precipitous labor are at increased risk for:
a. perineal lacerations.
c. urinary retention.
4. An Rh-negative mother delivers an Rh-positive infant, and alloimmunization (production of Rh antibodies in the mother) occurs. In this case, the risk of hemolytic disease is greatest in:
a. subsequent Rh-negative fetuses.
b. the current Rh-positive infant.
c. subsequent Rh-positive fetuses.
5. A patient at 34 weeks' gestation in a low-risk pregnancy who reports decreased fetal movement over the preceding hour should be instructed to:
a. report to her primary medical provider for immediate assessment.
b. have something to eat or drink, lie on her left side, and count fetal movements over the next 1-2 hours.
c. increase her physical activity.
Answers and Explanation
1. C: The greatest risk to the newborn infant occurs with a vaginal delivery during a primary genital herpes simplex virus (HSV) infection. Infection most commonly occurs by direct transmission, rather than across the placenta. The risk of transmission during vaginal delivery with an active primary infection is approximately 50%. Neonates with symptomatic HSV infection are often critically ill and may suffer chronic complications as a result of the neonatal infection. Risk of transmission to the infant with vaginal delivery during an active secondary HSV infection drops significantly to less than 5%. Cesarean section is recommended for women with signs of an active primary or secondary genital HSV outbreak around the time of delivery. Transmission is low in patients with a history of genital HSV infection who have no signs or symptoms of an active outbreak around the time of delivery.
2. B: Fetal heart rate variability reflects the interplay between cardiac responsiveness and the sympathetic and parasympathetic nervous systems. Baseline fetal heart variability refers to the degree of fluctuation in the fetal heart rate around the baseline. An amplitude of 6-25 beats/min in fetal heart rate variability (moderate variability) is considered normal. Decreased fetal heart rate variability is the best predictor of fetal compromise. Causes of decreased fetal heart rate variability include hypoxia, acidosis, gestational age under 32 weeks, fetal anomalies, central nervous system depressant medications, fetal tachycardia, and preexisting fetal neurologic abnormalities. Marked fetal heart rate variability of more than 25 beats/min amplitude (saltatory variability) is usually caused by early hypoxia, as occurs with umbilical cord compression, and is considered a nonreassuring pattern.
3. A: Precipitous labor is defined as labor that leads to delivery of the infant in less than 3 hours. A major predictive factor for precipitous labor is a history of previous precipitous labor. Precipitous labor may be anticipated if there is rapid cervical dilation, rapid fetal descent, or intense, frequent uterine contractions. Maternal risks with precipitous labor include cervical, vaginal, and perineal injury; postpartum hemorrhage as a result of both lacerations and uterine atony; and unaccompanied precipitous delivery. Fetal risks include hypoxia secondary to uterine hypertonicity and brachial plexus injury as a result of rapid descent and delivery. Precipitous labor in the group B Streptococcus-positive patient may not allow adequate time for administration of prophylactic antibiotics.
4. C: When an Rh-negative patient is pregnant with an Rh-positive fetus, any maternal exposure to fetal Rh-positive blood (e.g., spontaneous or therapeutic abortion, antepartum hemorrhage, delivery) can lead to sensitization or production of Rh antibodies in the maternal circulation. When maternal exposure (and sensitization) to fetal blood occurs at the time of delivery, the first Rh-positive infant is not affected. Subsequent Rh-positive fetuses in the sensitized Rh-negative mother are affected (often severely) by the hemolysis that occurs when maternal Rh antibodies cross the placenta and destroy fetal red blood cells. Rh-negative fetuses are not affected as their blood cells do not have Rh antigen. Rh-negative pregnant patients (who have not been sensitized) are given Rhogam (Rh immune globulin) to prevent sensitization when there is a reasonable likelihood of maternal exposure to Rh-positive fetal blood.
5. B: Decreased fetal movement has been associated with fetal distress and death. There is no established standard for a normal number of fetal movements in a given time period. As a general rule, four fetal movements in 1 hour or ten fetal movements in 2 hours is considered reassuring. Patterns of fetal movement are dependent on multiple factors, including time of day, location of the placenta, maternal medications, and the fetal sleep cycle. Low-risk patients reporting decreased fetal movement of less than 2-3 hours duration can be instructed to count fetal movements and inform the health care provider if there are less than ten movements in 2 hours (after 32-34 weeks' gestation). It has not been definitively demonstrated that prompt evaluation of decreased fetal movement results in improved fetal outcomes.
Last Updated: 03/01/2017